The couple's marriage had been troubled, said Clarissa Coleman, Valerie Robinson's sister. She said the couple had been married about 27 years.

Valerie Robinson arrived for work about 6:10 a.m. at Tompkins High School, 4400 Falcon Landing, when her estranged husband approached in the parking lot and shot her, officials said. He then was seen driving away in a pickup.

Valerie Robinson worked in the school cafe­teria, according to Steve Stanford, spokesman for the Katy Independent School District.

Two coaches performed CPR on the woman, who was later pronounced dead at Katy Memorial Hermann Hospital.

Rifle found at scene

Authorities tracked her husband to a home in Brookshire.

He held them at bay until about 10:30 a.m., when a SWAT team entered the home and found his body in the front bedroom. Robinson had shot himself in the head, according to DPS Sgt. John Sampa. It was not immediately known if a .22-caliber rifle found at the scene was the weapon used at the school.

Coleman said the couple often argued and her sister would leave their home determined to end the relationship. But she returned each time, mainly because the women's father lived with the couple.

Coleman said her sister's husband lost his job at a chemical plant that closed about two years ago.

Stormy relationship

The couple recently fought and her sister had moved out of the house, Coleman said. She said her sister planned to leave her husband and that he had been stalking her sister, often following her to the school where she worked.

Laticia Upshaw grew up with Valerie Robinson, and described her as a loving, caring person who liked going to work and getting the cafeteria prepared for students.

"She never had any bad vibes toward anyone," said Upshaw, a security officer at Katy High School.

Kendra McKinney said she had known the Robinsons for a long time, and they had always seemed happy.

"Nobody would ever expect this because she was a sweet lady and he was a good guy," McKinney said.